The San Salvador River in northern Chile is a tributary of the Loa, the only river that traverses the Atacama Desert from the mountains to the Pacific. Recent investigations along the San Salvador River revealed the presence of a Formative period village site and associated cemetery approximately 110 km inland from the Pacific Ocean. Bioarchaeological and biogeochemical analyses conducted on human skeletal remains recovered from the San Salvador Cemetery allowed us to better understand the site's role as an intermediary for coast/interior relations during the Middle Formative (500 B.C. -A.D. 100). Evidence from material culture and human remains at San Salvador suggests that this population was involved in exchange networks that united the oases of the Atacama Desert with the Pacific Ocean. Isotopic data support this notion, as the population demonstrates great variability in both the protein (marine and terrestrial) and carbohydrate components of their diet. During this period, communal economies produced surpluses used in a network of exchange for foods, prestige goods, and ideas. These ties were not coincidental but, rather, part of a regional economic structure that remains only partly explored.